Attorney General Eric Holder took aim Tuesday at "Stand Your Ground"-style laws — such as the one that figured into the George Zimmerman case — saying they may encourage violence and "undermine public safety."

"It's time to question laws that senselessly expand the concept of self-defense and sow dangerous conflict in our neighborhoods," Holder said in a speech to the NAACP in which he again called the death of Trayvon Martin “unnecessary.”

"There has always been a legal defense for using deadly force if — and the 'if' is important — if no safe retreat is available. But we must examine laws that take this further by eliminating the common sense and age-old requirement that people who feel threatened have a duty to retreat, outside their home, if they can do so safely.

"By allowing — and perhaps encouraging — violent situations to escalate in public — such laws undermine public safety. The list of resulting tragedies is long and, unfortunately, has victimized too many who are innocent.

"It is our collective obligation. We must 'stand our ground' to ensure that our laws reduce violence and take a hard look at laws that contribute to more violence than they prevent."

More than 20 states have so-called "Stand Your Ground" laws, which became the subject of national debate after Zimmerman, 29, said he fatally shot an unarmed Trayvon Martin, 17, in self-defense on Feb. 26, 2012, in Sanford, Fla.

Zimmerman did not invoke Florida’s "Stand Your Ground” law and ask for an immunity hearing before the trial, but the jury that acquitted him received instructions that borrowed language from the statute, specifying that if “he was attacked in any place where he had a right to be, he had no duty to retreat and had the right to stand his ground and meet force with force.”

The lobbying arm of the National Rifle Association didn't hold back in its criticism of Holder's speech.

"The Attorney General fails to understand that self-defense is not a concept, it's a fundamental human right. To send a message that legitimate self-defense is to blame is unconscionable, and demonstrates once again that this administration will exploit tragedies to push their political agenda," said Chris W. Cox, the executive director of the NRA's Institute for Legislative Action.

Holder's comments, in a long-planned address to the civil rights group, came amid other calls for a “Stand Your Ground” rollback.

The Rev. Al Sharpton, president of the National Action Network and an MSNBC host, announced plans Tuesday for a campaign by clergy to get the laws off the books. A group of protesters marched on Florida Gov. Rick Scott’s office to demand a special session of the legislature to view Florida’s law.

A spokeswoman for the governor said that soon after Martin’s death, he convened a bipartisan task force to review the law. “The task force recommended that the law should not be overturned, and Governor Scott agrees,” she said.

Although the NAACP speech marked Holder’s first comments on "Stand Your Ground,” he has addressed the Zimmerman case numerous times since the Justice Department opened a probe into the shooting weeks after Martin was killed.

George Zimmerman leaving the courtroom after being found not guilty on July 13.Joe Burbank via EPA

Holder, the nation’s first black attorney general said during Tuesday’s speech that Martin’s death reminded him of several incidents from his own past in which he was stopped by police even though he was doing nothing wrong.

He recounted how he sat down with his 15-year-old son to talk about the case “not to burden him with the baggage of eras long gone, but to make him aware of the world he must still confront.”

He reminded the audience that the Justice Department investigation remains open but was careful not to suggest that Zimmerman would be hit with civil rights charges.

Sharpton and other Martin supporters have been pressing Holder to ramp up the Zimmerman probe, but legal experts say federal hate-crime charges are unlikely given the available evidence.

"Usually when you have a successful prosecution, you have multiple statements made by the defendant about the victim's race while the defendant is attacking, or you have a group of people that went out looking for someone of a particular race to attack," said Samuel Bagenstos, a former top official in the Justice Department's Civil Rights Division.

"Proving what's on somebody else's mind is as difficult thing to do in the law as possible."

Martin’s supporters have said Zimmerman, a neighborhood watch volunteer who is of white and Hispanic descent, had a history of calling police to report “suspicious” black males in his gated community.

During a call to a non-emergency line when he spotted Martin walking around, he only mentioned he was black when asked about his race by the dispatcher. He also referred to “f---ing punks” and complained, “These guys always get away.”

Defense lawyer Mark O’Mara has said race played no factor in the confrontation between Zimmerman and Martin. He said his client’s background shows that he is a “non-racist.”

The only juror to speak about the deliberations and acquittal told CNN this week that no one on the six-woman panel believed race played a role.

George Zimmerman has sued NBC Universal for defamation. The company strongly denies the allegation.